Technical informational / commercial investigation
Two-Wire Video Intercom Wiring Diagram
Wiring and cabling guide
Confirm the exact equipment models, cable types, power capacity, distances and current manufacturer instructions before installation. Terminal names and ratings vary between products.
Main diagram
Equipment list
- Door Station - Two-wire outdoor station
- Two-Wire Distributor - Bus distribution
- Indoor Monitor 1 - Resident / reception station
- System Power Supply - Manufacturer-specific supply
- Indoor Monitor 2 - Optional additional station
- Router / LAN - Optional app gateway
Cable schedule
Use the diagram reference to follow the same connection from the main diagram into the detailed explanation below.
| Diagram ref | From | To | Cable type | Core count | Power or data | Maximum distance | Purpose / important notes |
|---|---|---|---|---|---|---|---|
| C1 | Door Station | Two-Wire Distributor | Approved two-wire bus | 1 approved pair / 2 conductors | Data/control | Not stated | Two-wire bus |
| C2 | Two-Wire Distributor | Indoor Monitor 1 | Approved two-wire bus | 1 approved pair / 2 conductors | Data/control | Not stated | Monitor bus |
| C3 | Two-Wire Distributor | Indoor Monitor 2 | Approved two-wire bus | 1 approved pair / 2 conductors | Data/control | Not stated | Additional monitor bus |
| C4 | System Power Supply | Two-Wire Distributor | Manufacturer supply cable | Confirm from the exact device functions | Data/control | Not stated | System power |
| C5 | Indoor Monitor 1 | Router / LAN | Cat6 or Wi-Fi to model | 4 twisted pairs / 8 conductors | Data/control | Not stated | Optional LAN |
No maximum distance is invented. Where the exact figure depends on Ethernet design, voltage drop, current draw or the selected device, the schedule tells the installer to confirm it.
What the wiring actually is
Match each C reference to the same label on the main diagram and cable schedule. The line name alone is not a complete cable specification, so this table explains the physical cable, conductor or pair use, what it carries and how it normally terminates.
| Diagram ref | Cable shown | Physical path | Cable construction | Conductors or pairs | What it carries | Normal termination | Confirm before installation |
|---|---|---|---|---|---|---|---|
| C1 | Approved two-wire bus | Door Station to Two-Wire Distributor | One manufacturer-approved copper pair. Depending on the system this may be an untwisted pair, twisted pair or a selected pair from suitable multicore/Cat cable. | Two conductors; polarity, branching and distributor requirements are system-specific. | The proprietary bus may combine power, audio, video and control. It is not ordinary Ethernet even when Cat cable is used. | The exact two-wire distributor, hub or device terminals specified by the manufacturer. | Permitted cable type/gauge, polarity, total distance, branch topology, device count and whether existing joins are allowed. |
| C2 | Approved two-wire bus | Two-Wire Distributor to Indoor Monitor 1 | One manufacturer-approved copper pair. Depending on the system this may be an untwisted pair, twisted pair or a selected pair from suitable multicore/Cat cable. | Two conductors; polarity, branching and distributor requirements are system-specific. | The proprietary bus may combine power, audio, video and control. It is not ordinary Ethernet even when Cat cable is used. | The exact two-wire distributor, hub or device terminals specified by the manufacturer. | Permitted cable type/gauge, polarity, total distance, branch topology, device count and whether existing joins are allowed. |
| C3 | Approved two-wire bus | Two-Wire Distributor to Indoor Monitor 2 | One manufacturer-approved copper pair. Depending on the system this may be an untwisted pair, twisted pair or a selected pair from suitable multicore/Cat cable. | Two conductors; polarity, branching and distributor requirements are system-specific. | The proprietary bus may combine power, audio, video and control. It is not ordinary Ethernet even when Cat cable is used. | The exact two-wire distributor, hub or device terminals specified by the manufacturer. | Permitted cable type/gauge, polarity, total distance, branch topology, device count and whether existing joins are allowed. |
| C4 | Manufacturer supply cable | System Power Supply to Two-Wire Distributor | Dedicated stranded copper power cable sized for supply voltage, continuous/inrush current and voltage drop; commonly two-core for DC positive and negative. | Two conductors for DC power unless the manufacturer specifies a proprietary loom or additional monitoring cores. | ELV DC power or the named protected supply. Never infer voltage from cable colour. | Correctly fused PSU/device terminals with observed polarity; manufacturer battery leads remain unmodified. | Required voltage, polarity, load/inrush current, fuse, cable size, voltage drop, battery capacity and separation from 230-240 VAC. |
| C5 | Cat6 or Wi-Fi to model | Indoor Monitor 1 to Router / LAN | Solid-copper Cat5e or Cat6 balanced Ethernet cable; Cat6 is the normal new-install choice. Fibre may replace copper for distance or electrical isolation. | Four twisted pairs / eight conductors, terminated consistently to T568A or T568B. | Ethernet data only unless the named port is specifically documented as PoE. | RJ45 network termination or the stated SFP/fibre interface. | 90 m permanent link / 100 m channel for copper Ethernet, port role, VLAN and whether the port supplies PoE. |
Are any resistors required?
| Circuit | Resistor required? | Where it belongs | How to select it |
|---|---|---|---|
| IP Ethernet/PoE or proprietary two-wire/four-wire intercom path | Normally no external EOL resistor | Not applicable | Use only termination or distributors specified by the intercom manufacturer. |
| Door strike, maglock or gate-relay path | Not normally a zone EOL resistor | At the lock/coil or receiving input only when specified | Inductive suppression and supervised-input resistors are different components. Follow both the intercom and lock/gate manuals. |
Never choose a resistor by cable colour or by the phrase "security cable". First identify the exact input, panel model and programmed supervision mode. An EOL resistor belongs at the end of the supervised circuit; placing it across the panel terminals defeats cable supervision.
Power requirements
Confirm the selected equipment's supply method, PoE class or DC input, total load and backup requirements before ordering. Keep lock power separate from data-path assumptions, calculate voltage drop for low-voltage loads, observe battery polarity and isolate any 230-240 VAC work to an appropriately licensed electrician.
How the wiring path works
Read the physical cable path first, then power, relay or I/O paths, network addressing and finally app or cloud registration. A device that appears offline may have a physical link, power, addressing or configuration fault; Wi-Fi and cloud registration should not be used to hide an incorrect LAN design.
Practical installation sequence
- Confirm every exact device model and current manual.
- Confirm cable types, routes, separation and distances.
- Check PoE or DC power capacity and site voltage drop.
- Mount and cable devices with power isolated.
- Test continuity, polarity and earth/surge arrangements where applicable.
- Power one subsystem at a time.
- Activate and address network devices.
- Configure relay, call or recording behaviour only after the physical path works.
- Test local operation, remote operation and failure modes separately.
- Record final models, IP addresses, cable IDs, settings and diagram revision.
Common mistakes
- Assuming a port provides PoE without checking the port and total switch budget.
- Confusing a recorder's isolated camera ports with its main LAN uplink.
- Powering a lock from an unsuitable relay or supply.
- Guessing normally-open, normally-closed, polarity or resistor details.
- Ignoring voltage drop, surge exposure or power-failure behaviour.
- Treating app setup as proof that the physical cabling is correct.
Troubleshooting
| Symptom | Likely cause | Test | Corrective action |
|---|---|---|---|
| Device has no power | Incorrect supply method or exhausted PoE budget | Check port status and measure only with the correct procedure | Match the power source to the exact device manual |
| Device powers but is offline | Wrong LAN path, addressing or activation state | Confirm link lights, subnet, gateway and device state | Correct physical LAN and addressing before cloud setup |
| System works locally but not remotely | Internet, DNS, account or cloud registration issue | Prove local operation first, then test WAN services | Correct router or account configuration; do not recable a working local link |
| Relay or lock action fails | Wrong contact logic, power path or load assumption | Test relay and lock supply as separate subsystems | Use the exact manual and suitable lock PSU; confirm egress requirements |
Compatible products and categories
Exact product links above were confirmed on the current Security Wholesalers site on 2026-07-19. Category links are used when an exact active compatible product was not confirmed.
Related diagrams
Frequently asked questions
Can I buy cable using this guide?
Use the cable schedule and buying list to shortlist the cable, then confirm the exact equipment model, route, distance, environment and manufacturer requirements before ordering.
Can cable distance or power capacity be assumed from this drawing?
No. Confirm the selected devices, PoE budget, voltage drop, cable construction and current manufacturer instructions.
Where do terminal names and resistor values come from?
They must come from the exact current manual for the selected model. Do not transfer terminal names, polarity or resistor values from a similar product.
Can this replace the manufacturer manual?
No. It is a planning and support reference only and does not replace manufacturer instructions, licensed work, fire engineering, egress assessment or site commissioning.
Technical references
| Manufacturer | Document | Revision | Relevant pages | Reference | Accessed |
|---|---|---|---|---|---|
| Selected equipment manufacturers | Selected equipment manuals and project network/cabling design | To be recorded during technical review | Terminal pages not used in this layout | Exact manual to be recorded | 2026-07-19 |
Diagram revision: 1.0. Confirm the exact current manual for the selected equipment before installation.
Australian installation and safety notice
General guide only. Confirm current manufacturer instructions and site requirements. Work involving 230-240 VAC must be completed by an appropriately licensed electrician. Fire-release interfaces, emergency exits and door locking require project-specific compliance assessment. Keep mains and ELV cabling appropriately separated, isolate power before work, observe battery polarity and calculate voltage drop for the real load and cable run.